Correspondents said many voters, especially younger ones, had not been expected to turn out.

"I can't say how many of my friends will vote; most were not very enthusiastic,'' retiree Rachid Bahriz told Reuters news agency after voting in Algiers.

Another woman voting in Algiers told the AP news agency that Algerians "need new blood".

"But I think we should prioritise stability and peace," she said.

Police violently broke up a protest organised by the Barakat group in Algiers on Wednesday and arrested some of its members, AFP reports.

More than 260,000 police were deployed to protect 50,000 polling booths, the agency reports.

Mr Bouteflika's main challenger, Ali Benflis, said he would not tolerate any attempt to rig the election in favour of the president.

"In case there is fraud I will not shut up. This does not mean we will push for chaos, because we have opted for stability," he said.

Mr Bouteflika took office in 1999 when Algeria was still caught up in a civil war between the military and Islamist militants and has been credited by supporters for curbing the conflict and restoring some economic stability.

He scrapped constitutional rules in 2008 limiting him to two terms in office.